Stringed instrument



July 13, 1943. c. BIEDERMAN 2,323,969

STRINGED INSTRUMENT Filed April 28, 1942 FQ'J.

Clare/ce ,Bieder/nm.'

INVENTOR ATTORNEYS Patented July 13, 1943 UNITED STATES PATENT OFFICE2,323,969 STRINGED INSTRUMENT Clarence Biederman, Lima, Ohio ApplicationApril 28, 194,2,v Serial No. 440,836

3 Claims.

The present invention relates to improvements in stringed musicalinstruments and more particularly to means for varying the tension ofthe strings thereof.

An object of the invention is to provide a string tension varying deviceof generally improved design.

Another object of the invention is to provide a device of the aforesaidcharacter wherein the tension of one or more strings may be varied uponmovement of a single operating element.

A further object of the invention is the provision of a device of theabove character which is relatively simple in construction and which maybe quickly and easily operated.

Other objects and advantages of the invention will become apparent asthe description progresses.

In the accompanying drawing forming a part of this speciiication and inwhich like numerals are employed to designate corresponding partsthroughout:

Figure l is a fragmentary plan View of a stringed instrument showing theinvention applied thereto,

Figure 2 is a side elevational View ofthe same,

Figure 3 is an enlarged section taken on line 3 3 of Figure 1 with theoperating handle in raised position,

Figure 4' is a transverse on line 4 4of Figure 3,

Figure 5 is a section taken on line 5 5 of Figure 3, and

Figure 6 is a section viewed from line 6-6 of Figure 3 with the cover inseparated relation.

Referring in detail to the drawing, wherein for the purpose ofillustration is shown a preferred example of the invention, I6 generallydesignates a stringed instrument, in the present example an electricHawaiian guitar, having strings II, I2, I3, I4, I5 and I6 extended tothe rear end of the body or sound box.

To the rear end of this instrument I@ is fastended a channel-shapedsupport bracket I'I which may be formed of sheet metal providing a pairof complementary elongated side plates I8 arranged vertically of theinstrument and projecting above the top of the sound box. Between theplates I8 is provided a vertical web portion I9 having top and bottomportions bent inwardly to form flanges 2G and 2I disposed against thetop and bottom of the instrument, as shown to advantage at Figure 4, Theweb porion I9 and the bottom flange 2| may be rmly secured to theinstrument body by screws sectional view taken 22 while the upperangular portion of the web is preferably shaped to form an outwardlyprotruding transverse lip 23. Adjacent the top edge of each side plateI8 is provided a transverse slot 2d opening into the outer edge whilethe bottom portion is cut out to provide an angular recess 25.

Journaled on and extending transversely between the side plates i8 is arotary member 26 in the form of a cylindrical elongated barrel formed atthe ends with reduced journals 2l adapted to be rotatably extendedthrough the bearing slots 24, The barrel 26 is shaped to provide, ataxially spaced intervals, a plurality of` circumferential grooves 2Sextending partially about the barrel to form cam portions or sectionshaving arcuate segments of an exterior radius corresponding to theradius of the barrel and segments of reduced radius, shown to advantageat Figure 6, the proles of these cam sections varying as to the extentof the reduced grooved portions and as to the circumferentialarrangement thereof, as best shown at Figure 3.

Supported on and extending between the side plates i8 below and inwardlyof the barrel 26 is a shaft 29 parallel with the barrel and of smallerdiameter. This shaft 29 supports thereon a plurality of rocker elements3U of L-shaped formation having right angular arms and provided withtransverse bores 3I at the juncture of the armsfor rocker mounting onthe shaft 29. These rocker arms are spaced on the shaft by means ofsleeves and spacing collars 32 and 33 respectively, tov assumepredetermined coacting positions with relation to the grooved camsections oi the barrel. In the embodi ent shown, a plurality of rockers36 are formed so that the right angular arms are of approximatelyuniform width. One of the rocker elements indicated at S15 is shaped sothat one arm thereof is enlarged to form a lateral extension 35. Theupper end portions of the upstanding arms of the rocker elements areformed with apertures 36 designed for connection therewith of one end ofcertain strings of the musical instrument, The opposite, approximatelyhorizontal, arm of each of the rocker elements 36 is formed with aninteriorly threaded aperture E6' adapted to receive therein a screw 3'!which is adjustable transversely of the arm and which may be secured inadjusted position by a nut 3S. The rocker element 34 carries two of theadjustable screws 3i in spaced relation, as illustrated at Figure 3.

To the protruding end of each of the journais 2 is secured the inner endof a radially disposed arm 39, these arms being disposed for connectionwith the ends of a transverse bar lill forming an approximately U-shapedhandle for turning the barrel.

On the support member I'! is normally positioned a cover il embodying apair of end plates 2, corresponding to the end plates I8, connected ,bya top wall 43 and an outer wall 44. In the upper portions oi the plates42 are provided slots i5 adapted to be slidably tted over the journals 2when the cover is in closure position, as shown in Figures 3 and 4. Thecover is removably fastened on the holder bracket by means of screws i5engageable with registering apertures ll'! in these elements.

In the example illustrated, the instrument I is equipped with sixstrings, the string Il of which has its rear end or terminal secured inxed position to the instrument, as shown to advantage at Figure 1, whilethe remaining ve strings are extended rearwardly for connection with therespective rocker elements and 34. The inner or upper ends of theadjusting screws 3'! on the rocker elements project from the arms forengagement with the cam sections of the barrel so that upon arrangementof the barrel in varying angular positions the screws 3'! will assumeregistration with the protruding or the recessed grooved portions of thecams. In the arrangement shown, when the operating handle i8 is inuppermost position with the arms 39 thereof disposed vertically, five ofthe cams will be disposed so that their portions of greatest radius willcontact with the screws 3'! of the rocker elements to dispose saidelements in such arrangement that the strings l2 to I6 inclusive, willbe under greatest tension. If the barrel is rotated in a clockwisedirection through an arc of ninety degrees it will attain a positi-on,with the handle extending rearwardly, as shown at Figures 1 and 2,wherein the inner ends of the screws 3'! can enter the grooves 28 underthe tension of the strings and thereby decrease or slacken the tensionand change the pitch of the strings. When the rockers are thus relatedto the barrel the upstanding arms thereof may be disposed to bearagainst the lip 23 of the holder. When the handle is swung to a thirdposition, downwardly with relation to the holder, as shown in dottedlines at Figures 2 and 4, the screws of certain of the rockers willremain in the grooves so that certain of the strings such as the stringsI3 to I6 remain slackened. Due to the arrangement of the barrel groovein coacting relation with the adjusting screw in the 01T- set portion ofrocker 34, however, the screw of this rocker will be depressed by thecam so as to restore the string l2 to a condition of increased tension.

In each of the respective tuning positions of the cam member or barrel,which are attained 4by selective movement of the handle, a plurality ofstrings of the instrument are tensioned to effect a predetermined tuningor chord. In addition to various tuning combinations obtainable uponangular adjustment of each barrel, further tuning combinations can bemade available by interchanging barrels on the holder bracket. It

will also be apparent that the invention is applicable to stringedinstruments of various forms and having a varying number of strings.

It is to be understood that the form of my invention herewith shown anddescribed is to be taken as a preferred example of the same and thatvarious changes relative tc the material, size, shape and arrangement ofparts may be resorted to without departing from the spirit of theinvention or the scope `of Ithe subjoined claims.

Having thus described my invention, I claim:

l. In a tensioning device for a musical instrument having a plurality ofstrings, a support adapted for attachment to the instrument, a pluralityof angular rocker elements pivotally mounted on the support to rock inthe direction of the strings, a projection carried by each rockerelement, means at one end of each rocker for engaging a string, a barrelpivotally mounted on the support parallel with the pivot axes of thesaid rocker elements, the said barrel having a plurality ofcircumferential cam forming sections against which the projections oftherespective rocker elements are held by the tension of the strings, andmeans attached to the barrel for turning the same to vary the tension ofthe strings.

2. In a tensioning device for a musical instrument having a plurality ofstrings, a support adapted for attachment to the instrument, a pluralityof angular rocker elements pivotally mounted on the support so as torock in the direction of the strings, an adjustable projection carriedby each of the rocker elements, each of the said rockers having one endadapted for engagement with a string, a barrel pivotally mounted on thesupport parallel with the axes of the said rockers, the said barrelhaving a plurality of circumferential arcuate grooves at longitudinallyspaced intervals coacting with corresponding arcuate portions of thebarrel surface to provide cam sections against which the projections ofthe respective rocker elements are' pressed by the tension of thestrings, and means attached to the barrel for selectively turning thesame to vary the tension of the strings.

3. In a tensioning device for a musical instrument having a plurality ofstrings, a support adapted for attachment to the instrument, a pluralityof angular rocker elements pivotally mounted on the supportso-as to rockin the direction of the strings, an adjustable projection carried byeach of the rocker elements, each of the said rockers having one endadapted for engagement with a string, a barrel pivotally mounted on thesupport parallel with the axes of the said rockers, the said barrel*having a plurality of circumferential arcuate grooves at longitudinallyspaced intervals coacting with corresponding arcuate portions of thebarrel surface to provide cam sections against which the projections ofthe respective rocker elements are pressed by the tension of thestrings, and a U-shaped handle having connection with the ends of thebarrel for selectively turning the latter to vary the tension of thestrings.

CLARENCE BIEDERMAN.

